2017年Java认证考试试题
使用Java语言的先进的面向对象特点，包括方法重载，方法覆盖，抽象类，接口，final，static和访问控制;实现文件的输入输出(I/O)。下面是小编整理的关于Java认证考试试题，希望大家认真阅读!
question 1)
which of the following lines will compile without warning or error.
1) float f=1.3;
2) char c='a';
3) byte b=257;
4) boolean b=null;
5) int i=10;
answer to question 1
question 2)
what will happen if you try to compile and run the following code
public class myclass {
public static void main(string arguments[]) {
amethod(arguments);
}
public void amethod(string[] arguments) {
system.out.println(arguments);
system.out.println(arguments[1]);
}
}
1) error can´t make static reference to void amethod.
2) error method main not correct
3) error array must include parameter
4) amethod must be declared with string
answer to question 2
question 3)
which of the following will compile without error
1)
import java.awt.*;
package mypackage;
class myclass {}
2)
package mypackage;
import java.awt.*;
class myclass{}
3)
/*this is a comment */
package mypackage;
import java.awt.*;
class myclass{}
answer to question 3
question 4)
a byte can be of what size
1) -128 to 127
2) (-2 power 8 )-1 to 2 power 8
3) -255 to 256
4)depends on the particular implementation of the java virtual machine
answer to question 4
question 5)
what will be printed out if this code is run with the following command line?
java myprog good morning
public class myprog{
public static void main(string argv[])
{
system.out.println(argv[2])
}
}
1) myprog
2) good
3) morning
4) exception raised: 'java.lang.arrayindexoutofboundsexception: 2'
answer to question 5
question 6)
which of the following are keywords or reserved words in java?
1) if
2) then
3) goto
4) while
which of the following statements are true?
1) methods cannot be overriden to be more private
2) static methods cannot be overloaded
3) private methods cannot be overloaded
4) an overloaded method cannot throw exceptions not checked in the base class
answer to question 16
question 17)
what will happen if you attempt to compile and run the following code?
class base {}
class sub extends base {}
class sub2 extends base {}
public class cex{
public static void main(string argv[]){
base b=new base();
sub s=(sub) b;
}
}
1) compile and run without error
2) compile time exception
3) runtime exception
answer to question 17
question 18)
which of the following statements are true?
1) system.out.println( -1 >>> 2);will output a result larger than 10
2) system.out.println( -1 >>> 2); will output a positive number
3) system.out.println( 2 >> 1); will output the number 1
4) system.out.println( 1 <<< 2); will output the number 4
answer to question 18
question 19)
what will happend when you attempt to compile and run the following code?
public class tux extends thread{
static string sname = 'vandeleur';
public static void main(string argv[]){
tux t = new tux();
t.piggy(sname);
system.out.println(sname);
}
public void piggy(string sname){
sname = sname + ' wiggy';
start();
}
public void run(){
for(int i=0;i < 4; i++){
sname = sname + ' ' + i;
}
}
}
1) compile time error
2) compilation and output of 'vandeleur wiggy'
3) compilation and output of 'vandeleur wiggy 0 1 2 3'
4) compilation and probably output of 'vandeleur' but possible output of 'vandeleur 0 1 2 3'
answer to question 19
question 20)
what will be displayed when you attempt to compile and run the following code
//code start
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